Tuesday 23 October 2012 13.46 EDT
First published on Tuesday 23 October 2012 13.46 EDT

Alex Salmond has been accused of misleading voters about the legal advice given to his government about the right of an independent Scotland to join the European Union.

The first minister has repeatedly said that Scotland would be an automatic member of the EU, be free to adopt sterling as its currency and would inherit all the UK's opt-outs on EU immigration and border controls. He has asserted that this position was supported by his government's legal advice.

But Salmond was forced to make a statement to the Scottish parliament late on Tuesday after opposition leaders accused him of "lying" and "covering-up" following an admission from his deputy, Nicola Sturgeon, that no specific legal advice had been given by Scottish law officers on EU membership.

Asked what that advice said, Salmond responded: "Well, you know I can't give you the legal advice or reveal the legal advice of law officers, but what you can say is that everything we publish is consistent with the legal advice we have received."

But in an unexpected disclosure to the Scottish parliament, which capped an already difficult day for Salmond after two SNP backbenchers resigned over Nato, Sturgeon revealed that the Scottish government had only sought legal advice from its law officers in the last week.

The Scottish government was due to appear at a two-day hearing in Scotland's highest civil court in December in an attempt to overturn a historic ruling by Rosemary Agnew, the Scottish information commissioner, that this legal advice should be published in the public interest. However, this court action – which has so far cost nearly £12,000 in legal expenses –will now be dropped, Sturgeon said. "I can confirm that the government has now commissioned specific legal advice from our law officers on the position of Scotland within the EU if independence is achieved," she said. "[The] Scottish government had previously cited opinions from a number of eminent legal authorities, past and present [but] has not sought specific legal advice." She also suggested that getting legal advice was only possible now that Salmond and David Cameron, the prime minister, had signed the "Edinburgh agreement" to legally establish the independence referendum.

She told MSPs that ministers had only recently requested that advice from its chief law officer, Frank Mulholland, the lord advocate, provoking audible gasps from opposition benches.

In a brief statement to MSPs, Salmond denied misleading voters but again said every Scottish government statement and policy paper on EU membership had drawn on its own legal advice, appearing to contradict Sturgeon's earlier statement. He said he was talking about "general advice", adding: "All of these documents are underpinned by legal advice by our own law officers. They have to be. That is the reality."

Paul Martin MSP, Scottish Labour's business manager, said: "It appears the first minister is a liar and used taxpayers' money to try to cover up his lies. [Alex] Salmond has started the debate on Scotland's future within the UK with barefaced lies that even embarrass his deputy."

Catherine Stihler, the Labour MEP for Scotland whose first freedom of information request led to Salmond's legal challenge, said: "When I attended the court of session in September the Scottish government must have known that their legal advice was just a blank sheet of paper. Thousands of pounds later and now we are told they are seeking legal advice. You couldn't make it up; it's lies, lies and more damned lies."

Alistair Darling, chairman of the pro-UK Better Together campaign, said the disclosure undermined the Scottish government's stance on EU membership, which contracted other legal opinions that Scotland would have to reapply to join the EU, may be forced to use the euro, and adopt the Schengen agreement on border controls.

Ruth Davidson, the Scottish Tory leader, stopped short of accusing Salmond of lying, but said: "This has been a cabinet cover-up right from the beginning, using taxpayers' money to try and hoodwink the Scottish people. This is conduct unbecoming of a first minister and his government and exposes the depths to which they will sink to realise their independence dream."

The controversy added to what was already a difficult day for Salmond, which saw his overall majority at Holyrood reduced to two seats.

Earlier on Tuesday, two rebel MSPs Jean Urquhart and John Finnie, resigned from the party in protest at an SNP conference vote at the weekend to join the nuclear-armed military alliance Nato.

Finnie, a former police officer who joined the SNP at 16 and has been an open critic of other Scottish government policies, said: "I cannot belong to a party that quite rightly does not wish to hold nuclear weapons on its soil, but wants to join a first-strike nuclear alliance."

It also emerged on Tuesday that a long-delayed Scottish government consultation on its independence referendum, which received 26,000 responses, had found widespread and at times heavy opposition to some of Salmond's key proposals for the referendum – particularly his desire for a two-question poll.

The document, published by Sturgeon, disclosed that 59% of respondents did not want a two-question referendum which included an option to vote for greater devolution – one of Salmond's main objectives. A two-option poll was only backed by 25%.

It found that 53% of respondents supported votes for 16- and 17-year-olds but once "standard campaigns" were taken out of the calculation, support fell to 45% in favour and 48% against. It found voters were split 33% to 27% in favour of voting on Saturdays.

The biggest vote in support of Salmond showed that 63% of respondents favoured his proposed referendum question: "Do you agree that Scotland should be an independent country?", and 59% agreed the vote should be held in autumn 2014.

Richard Baker, a Labour shadow minister, said: "Tuesday was a three-part 'scomnishambles' for this government."